Improvement in color expression and antioxidant activity of strawberry juice fermented with lactic acid bacteria: A phenolic-based research

The aim of this study was to investigate the impact of lactic acid bacteria fermentation on color expression and antioxidant activity of strawberry juice from the perspective of phenolic components. The results showed that both Lactobacillus plantarum and Lactobacillus acidophilus were able to grow in strawberry juice, promote the consumption of rutin, (+)-catechin and pelargonidin-3-O-glucoside, and increase the content of gallic acid, protocatechuic acid, caffeic acid and p-coumaric acid compared to group control. Lower pH environment in fermented juice was likely to enhance the color performance of anthocyanins and increase its parameters a* and b*, making the juice appear orange color. In addition, the scavenging capacity of 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and ferric reducing antioxidant capacity (FRAP) were improved and closely related to polyphenolic substances and strain's metabolites in fermented juice.